In eye surgery, such as LASIK (laser-assisted in situ keratomileusis) surgery, information about the eye may be gathered for use in the surgery. For example, the shape or thickness of the corneal tissue before surgery or the depth of cuts made during surgery may be measured. As another example, images of any scars within the corneal tissue due to previous surgeries may be taken.
An apparatus for cutting corneal tissue of an eye according to the known art is disclosed e.g. in WO 2011/003431 A1. Such an apparatus typically comprises a so-called suction ring which can be placed on the eye and which is attached to the eye by generating a vacuum between the suction ring and the anterior surface of the eye. The suction ring unit serves to prevent unwanted movements of the eye during refractive surgery or any other treatment of the eye by laser radiation. The laser radiation is shaped and guided by an optical unit typically comprising several optical elements for guiding and focussing laser radiation relative to the eye, in particular, relative to corneal tissue of the eye that is to be cut.
It is understood that, beside of LASIK, the invention can be used in connection with tissue incisions in a human eye, e.g., in keratoplasty (e.g., anterior or posterior lamellar keratoplasty, penetrating keratoplasty in corneal graftings), in lenticule extraction for the purpose of refraction correction, in the cutting of intercorneal ring segments for the purpose of stabilising keratoconus and protrusion of the cornea (e.g., for the insertion of intacs, i.e. small implanted ring segments for biomechanical stabilisation of the cornea), in cataract incisions, in presbyopia incisions in the crystalline lens, in intrastromal inlays, in keratotomy for astigmatisms, in corneal resection and such like.
WO 02/076355 A2 describes a method for minimal-to-non-invasive optical treatment of tissues of an eye and for diagnosis thereof wherein a three-dimensional imaging of tissue is performed by means of radiation re-emitted from corneal tissue. The re-emission is generated by the laser system also used for ablation.